Kx 250

i would think the best way to slow it down is to sell it and buy an XR250!

But i think adding a flywheel weight should help quite a bit to take a bit of the jolt out of it. I doubt adding the weight will cause reliabity issues.

Weve doubled up head gaskets on these bikes before with good results , and its cheap . Maybe retarding the ignition timing a bit could help also . Also may help let you run cheaper fuel .There are otherways that have been discussed here like powervalve disabling . Porting , Im sure MR GORR can build you a fast and seamless powerband if you want to . I like powervalves though .

lwilson250 retarded the timing on his bike and he was quite happy with it. :thumb:

I ride a 2002 Kx250 also. I use a weight (12 or 13 oz. I think) when I go trail riding in tight trails and hill climbing. It really makes the power more managable. It doesn't work very well for motocross, so I take it out when I race.

Buy a kdx. Just kidding. I have ridden a few bikes with flywheel wieght. It helps a bunch in my experience.

I have a 11 oz. fly wheel weight on my 2000 KX 250. It works great and a 13 oz. would work better in the mud. Dean I have considered disableing my power valve for the muddy winter trail riding. Can this lead to any damage other than maybe gummed up valves? Anyone out there tried this and what is the power like? I would like to create KDX 250 style power. Can anyone tell me if a bull dog type of 1st gear can be bought and put in the gear box (maybe from a early 90's KDX 250)? Thanks

Originally posted by DEANSFASTWAY
Porting , Im sure MR GORR can build you a fast and seamless powerband if you want to . I like powervalves though .

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That he can and it is a much better solution than a flywheel weight. I sold the weight I had for mine. Porting is the way to go imo.

Most of the guys I know out here in the East like flywheel weights on their KX 250s and some even like them for MX .The KX seems real herky jerky at slow speeds in the woods or rocks and mostpeople who I know who run it say the bike stalls less . Add on weights can be a disaster if they ever come loose though . KAW sells different weight flywheels for some bikes (125s for sure) maybe they sell something heavier off the shelf . I beleive that the 250 KXs have alot of static compression and thats why they hit hard . -djr-: I dont think that youll really hurt anything by disabling the valves as long as you run good fuel and listen to the engine for pinging /detonating . When the power valve opens it bleeds off comp and keeps this from happening . When you disable the P/V on a 250 it hasalot of bottom & mid and wont rev out real well , somewhat stops the rush of revs past mid range . CR250 owners who arent careful when replacing top ends can tell you how it is ,since it can be sort of tricky to line up the P/V actuator levers at the R/F cylinder base. I know six or seven guys that did that in the past few years ."New top end ,bike runs flat "My pal used to have a KDX 250 and it was a good bike but it was a sled . I think the trans shafts and stuff are different now in the newer style gearbox , I doubt you could swap first but you never know . KDX 250 used a different flywheel than KX . I have a friend whos kid is just learning so he made a restricto sleeve to fit in the CR 125 exhaust flange and he says it mellowed out the bike . Strange to think becuse I usually spend my time trying to make power..??? Have fun in the woods DEAN

Originally posted by Senior KX Rider



That he can and it is a much better solution than a flywheel weight. I sold the weight I had for mine. Porting is the way to go imo.

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i disagree! :confused:

Yes porting will create a seamless power band, but i dont think it will make the power more "sedate". In my experience, allthough the power torque was smoother and easier to ride, the bike felt quite the oposite than "more sedate". Ive said it before, but the last place i want my eric gorr tuned MXer is anywhere near imovable objects such as trees! :yeehaw:

Xharley
My 2000 kx 250 has full Pro-Curcuit woods porting, pipe, silencer, and 11 oz. flywheel weight and it is very controllable in the woods. Ride it a gear high and it is excellent until I hit slick clay mud. If I am going up a tough hill and it is slick, somewhere about 6,000 rpm the good power turns to yee-haw wheel spin and a sideways bike. It doesn't matter what gear I am in the motor is so strong. I am trying to find a way to tune this wheel spin out. Considering 13:51 gearing and use 4th and 5th gear more but the transmission ratios are short now and it goes through the gears very quick.

Thanks Dean